1. Field of the Invention
The present invention relates to a novel optically active compound and a liquid crystal composition containing the same. More particularly, it relates to an optically active compound useful as a component of a ferroelectric liquid crystal composition and a ferroelectric liquid crystal composition containing the same.
2. Description of the Prior Art
Although the practical use of a liquid crystal element has started with the application thereof to the display of a watch or an electronic calculator, it is now applied to a wider field including pocketable televisions, various displays and optoelectronic elements. Most of the liquid crystal display elements now in use are of TN display type wherein nematic liquid crystal materials are used. Since this type of display is of photoreception type, it has disadvantages in that the speed of response is low and that the displayed images cannot be seen at some angles of vision, though it has advantages in that the eyes get little tired and that the power consumption is very low. In order to overcome these disadvantages, a display system using a ferroelectric liquid crystal has recently been proposed. Even in a display element of this type, like in the case of the above mentioned TN liquid crystal display element, a ferroelectric liquid crystal must be practically used in a state mixed with several liquid crystal or non-liquid-crystal compounds, i.e., as a so-called ferroelectric liquid crystal composition, in order to satisfy various characteristics.
On the basis of this idea, Japanese Patent Laid-Open No. 44548/1988 proposed the use of an optically active 2-methyl-1,3-propanediol compound as a component of a ferroelectric liquid crystal composition. However, such a ferroelectric liquid crystal composition is not sufficiently improved in the speed of response, if any. Accordingly, a further improvement in the speed of response of a ferroelectric liquid crystal composition has been expected in order to put the composition to practical use.